System Integration in Animal Physiology: Nervous, Endocrine, and Transport Mechanisms

System integration

A necessary process in living systems where coordination is needed for component parts to collectively perform an overall function.

Multicellular organisms

Organized in a hierarchy of organization.

System

A group of interacting component parts that act together to form a unified whole.

System integration in multicellular organisms

The process by which different physiological systems in the body coordinate and work together to maintain homeostasis and/or perform a function.

Communication in system integration

Depends on communication between the component parts.

Integration of systems in animal bodies

Occurs by hormonal signals, nervous signals, and transport of materials and energy in the blood.

Nervous system

A system that uses electrical signals within neurons and neurotransmitter molecules between neurons.

Endocrine system

A system that uses hormone molecules into the blood for signaling.

Speed of signal in nervous system

Very rapid.

Speed of signal in endocrine system

Slower.

Duration of signal in endocrine system

Longer (until hormone is broken down).

Duration of signal in nervous system

Shorter.

Control in endocrine system

Involuntary.

Control in nervous system

Voluntary or involuntary.

Transport of materials and energy

The blood transports nutrients, oxygen, hormones, and water required for metabolism and removes waste products such as carbon dioxide.

Function of the brain

To serve as the center of the nervous system in all vertebrate and most invertebrate animals.

Sources of information input to the brain

Includes multiple inputs about changing conditions of the body.

Neurons

Cells that transmit electrical impulses.

Glial cells

Cells that support both the structure and function of neurons.

Centralized control of the body

Allows for a rapid and coordinated response to multiple inputs.

Spinal cord

Acts as an integrating center for unconscious processes.

Conscious processes

Processes that involve awareness and deliberate control.

Unconscious processes

Processes that occur without awareness or deliberate control.

Organs of the central nervous system

Include the brain and spinal cord.

Two main tissue types of the central nervous system

Neurons and glial cells.

Reflexes

Basic responsiveness that can be mediated by the spinal cord.

Learning and memory

Require the information integrating capabilities of a centralized brain.

Conscious Processing

A type of processing that involves awareness and intentionality.

Unconscious Processing

A type of processing that occurs without conscious awareness or control.

Cell Body of a Neuron

The part of a neuron that contains the cytoplasm and nucleus.

Axon

A long single fiber that transmits electrical impulses away from the cell body of a neuron.

Dendrites

Multiple shorter fibers that receive signals from other neurons and convey them to the cell body.

Sensory Neurons

Neurons located in the skin and sense organs that convey messages from receptor cells to the central nervous system.

Photoreceptors

Sensory receptors that respond to wavelengths of light.

Chemoreceptors

Sensory receptors that respond to chemical signals, such as taste, smell, blood pH, and blood glucose concentration.

Mechanoreceptors

Sensory receptors that respond to mechanical stimulation, such as touch, pressure, vibration, and sound.

Thermoreceptors

Sensory receptors that respond to changes in temperature.

Cerebral Hemispheres

Parts of the brain that control muscle functions, speech, thought, emotions, reading, writing, and learning.

Primary Motor Cortex

A region of the cerebrum that controls voluntary movement via motor neurons to skeletal muscles.

Motor Neurons

Neurons that transmit signals from the central nervous system to muscles, stimulating them to contract.

Input to the Spinal Cord

Information received through sensory neurons that convey messages from receptor cells to the central nervous system.

Output from the Cerebral Hemispheres

Signals sent to muscles through motor neurons to coordinate movement.

Sensory Input

Information received from the environment through sensory neurons that is processed by the brain.

Environmental Conditions

Factors in the surroundings that can be detected by sensory receptors, such as light, temperature, and pressure.

Electrical Impulses

Signals that are conducted along the fibers of neurons to transmit information.

Skeletal muscles

Responsible for creating movement by pulling bones in different directions.

Motor Neuron

A neuron whose cell body is located in the central nervous system and whose axon extends to connect to a muscle gland.

Two-neuron circuit

A circuit where one motor neuron originates in the cerebral cortex and travels down the brainstem or spinal cord, forming a synapse with a second motor neuron.

Nerve

A bundle of neurons and supportive tissues surrounded by a protective sheath, part of the peripheral nervous system.

Nerve Structure

Includes a protective sheath and can contain either or both sensory and motor neurons.

Reflex

An automatic, involuntary response to a stimulus that occurs through neural pathways in the nervous system.

Reflex arc

The neural pathway involved in a reflex action, including receptors, sensory neurons, interneurons, motor neurons, and effectors.

Cerebellum

A part of the brain located in the back of the head, between the brainstem and the cerebrum, responsible for coordinating skeletal muscle contraction and balance.

Cerebellum - function

Includes maintenance of balance and posture, coordination of voluntary movements, and facilitation of motor memory.

Balance disorders

Conditions caused by a damaged cerebellum that affect the ability to maintain balance.

Coordination of voluntary movements

The cerebellum coordinates different muscle groups acting together in timing and force to produce fluid movements.

Motor memory

The ability to learn and remember coordination of muscle movements for specific actions, formed through practice.

Peristalsis

The involuntary control of the movement of material through the digestive system, coordinated by the enteric nervous system.

Central nervous system (CNS)

Responsible for the voluntary control of swallowing food and egestion of feces.

Enteric nervous system (ENS)

Controls peristalsis in the digestive system, ensuring coordinated passage of material through the gut.

Pain reflex arc

An example of involuntary responses with skeletal muscle as the effector, involving a single interneuron in the spinal cord.

Receptors

Sensory nerve endings that detect stimuli, such as pain in the hand.

Interneurons

Neurons that connect sensory neurons to motor neurons within the central nervous system.

Effectors

Muscles or glands that respond to signals from motor neurons.

Coughing

A reflex action triggered by something in the airway.

Blinking

A reflex action that protects the eye.

Sneezing

A reflex action triggered by irritation of the nose.

Pupillary accommodation

A reflex action that reduces the pupil size due to an object coming close.